The story

While investigators trudge through pig farms and remote villages in Mexico, searching for clues about the new swine flu, answers about the virus' origin may finally appear on a computer, based on genetic codes.

At the Department of Biomedical Informatics at Columbia University, researchers are using public databases to trace the origins of the 2009 H1N1 virus. They've found that the closest relatives to the new virus are viruses that were isolated from pigs in the United States in the past few years.

Their analysis, recently published in Eurosurveillance, suggests that the virus has at least two swine ancestors, one of them related to a virus isolated in North America in 1998.

Still, the relatives are distant, and it's premature to conclude that the virus came from the United States based on this analysis, said Raul Rabadan, study co-author and assistant professor at Columbia.

Influenza is like a small jigsaw puzzle with eight pieces, each with its own function, Rabadan said. The puzzle changes all the time, which is why exposure does not lead to total immunity and vaccines need to be updated yearly. Read full article »

All About Influenza • Centers for Disease Control and Prevention